diff --git a/include/mruby/internal.h b/include/mruby/internal.h
index 02e85d656..5611941da 100644
--- a/include/mruby/internal.h
+++ b/include/mruby/internal.h
@@ -114,6 +114,9 @@ struct RProc *mrb_closure_new(mrb_state*, const mrb_irep*);
 void mrb_proc_copy(mrb_state *mrb, struct RProc *a, struct RProc *b);
 mrb_int mrb_proc_arity(const struct RProc *p);
 struct REnv *mrb_env_new(mrb_state *mrb, struct mrb_context *c, mrb_callinfo *ci, int nstacks, mrb_value *stack, struct RClass *tc);
+void mrb_proc_merge_lvar(mrb_state *mrb, mrb_irep *irep, struct REnv *env, int num, const mrb_sym *lv, const mrb_value *stack);
+mrb_value mrb_proc_local_variables(mrb_state *mrb, const struct RProc *proc);
+const struct RProc *mrb_proc_get_caller(mrb_state *mrb, struct REnv **env);
 #endif
 
 /* range */
diff --git a/mrbgems/mruby-binding-core/src/binding-core.c b/mrbgems/mruby-binding-core/src/binding-core.c
index 8761fa031..73f0dc8dd 100644
--- a/mrbgems/mruby-binding-core/src/binding-core.c
+++ b/mrbgems/mruby-binding-core/src/binding-core.c
@@ -24,10 +24,6 @@
 # endif
 #endif
 
-void mrb_proc_merge_lvar(mrb_state *mrb, mrb_irep *irep, struct REnv *env, int num, const mrb_sym *lv, const mrb_value *stack);
-mrb_value mrb_proc_local_variables(mrb_state *mrb, const struct RProc *proc);
-const struct RProc *mrb_proc_get_caller(mrb_state *mrb, struct REnv **env);
-
 static mrb_int
 binding_extract_pc(mrb_state *mrb, mrb_value binding)
 {
diff --git a/mrbgems/mruby-binding/src/binding.c b/mrbgems/mruby-binding/src/binding.c
index de3147f68..311765171 100644
--- a/mrbgems/mruby-binding/src/binding.c
+++ b/mrbgems/mruby-binding/src/binding.c
@@ -8,7 +8,6 @@
 #include <mruby/internal.h>
 #include <mruby/presym.h>
 
-void mrb_proc_merge_lvar(mrb_state *mrb, mrb_irep *irep, struct REnv *env, int num, const mrb_sym *lv, const mrb_value *stack);
 const struct RProc *mrb_binding_extract_proc(mrb_state *mrb, mrb_value binding);
 struct REnv *mrb_binding_extract_env(mrb_state *mrb, mrb_value binding);
 typedef mrb_bool mrb_parser_foreach_top_variable_func(mrb_state *mrb, mrb_sym sym, void *user);
diff --git a/mrbgems/mruby-metaprog/src/metaprog.c b/mrbgems/mruby-metaprog/src/metaprog.c
index 67da9cd99..7063873c5 100644
--- a/mrbgems/mruby-metaprog/src/metaprog.c
+++ b/mrbgems/mruby-metaprog/src/metaprog.c
@@ -22,8 +22,6 @@ typedef enum {
   NOEX_RESPONDS  = 0x80
 } mrb_method_flag_t;
 
-mrb_value mrb_proc_local_variables(mrb_state *mrb, const struct RProc *proc);
-
 static mrb_value
 mrb_f_nil(mrb_state *mrb, mrb_value cv)
 {